Raye of sunshine.

Given his client's larger-than-life persona, it is a surprise to find that Amy Winehouse's manager Raye Cosbert is so unassuming. But behind the modesty is a man who has been the mainstay of Amy's success

He is one of the main driving forces behind the biggest musical success story of the year - and has possibly one of the toughest jobs - but Raye Cosbert is as unassuming as they come. In fact, the only obvious clue to anyone visiting his offices that this is where Amy Winehouse's manager is based is an unobtrusive gold disc hanging behind the reception desk to mark the first sales milestone of her career-changing second album Back To Black.

"I don't usually do things like this [interviews]," he lets on, as he descends the stairs to Metropolis' North London head office, where he works primarily as a promoter, but for the past 16 months has handled management for the Rehab star. "I don't like people knowing what I look like - they might start following me home!"

Cosbert's modesty and unassuming nature stretches to the fact that he did not even want to be photographed for this piece, but this should not play down just how important a role Cosbert has had in Winehouse's transformation from an artist with huge, unfulfilled potential to someone with the UK's biggest-selling album of the year and more than 1m album sales in America.

"There are two pivotal moments in Amy's career," says EMI Music Publishing managing director Guy Moot whose company publishes Winehouse, "the introduction of Raye and of Mark Ronson."

Cosbert began managing Winehouse in the spring of 2006, after her seven- year management relationship with Nick Shymanski at 19 Entertainment came to an end. The management opportunity, Cosbert says, arose by chance.

With Cosbert having promoted her live shows since 2003, the two already shared a healthy friendship and, when she found herself without management, she turned to him. "We had a chance meeting one day in Camden," Cosbert remembers. "She told me about her situation, said she'd heard that I was doing the odd thing management-wise and we just hit it off from there really."